Vessel with a multi-mode hull

ABSTRACT

A ship having a multi-mode hull where the draft, seakeeping, and payload-carrying capacity are varied to match the requirements of the required mission. For example, the ship has a hull with first and second hull portions and with an interconnecting hull structure, and has a ballasting system within the hull portions and operable to adjust the draft of the vessel in conjunction with the payload carried by the ship so that the ship can perform a designated mission. The hull is designed to have an adjustable hull depth according to the payload carried to perform the mission and augmented by the ballasting system so as to optimize draft, and thus hull mode, to meet mission requirements. As a result, the ship operates in four distinct modes as follows: very shallow draft (logistics mode), shallow draft (catamaran mode), moderate draft (SWATH mode), and deep draft (stealth/low-freeboard mode).

CLAIM OF PRIORITY

This application claims priority to U.S. Provisional Application Ser.No. 60/426,070 filed on Nov. 12, 2002, which is incorporated byreference.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to U.S. patent application Ser. No.10/712,777 entitled MISSION MODULE SHIP DESIGN and Ser. No. 10/712,987entitled METHOD AND SYSTEM FOR MISSION MODULE SWAPPING IN A VESSEL,which have a common filing date and owner, and which are in byreference.

BACKGROUND OF THE INVENTION

Modern Naval ships are typically designed to perform multiple types ofmissions, and are, therefore, referred to as “multi-mission” ships. Forexample, suppose a ship is designed for anti-submarine warfare, littoralwarfare, and anti-mine warfare. Such a ship may include a deck that hasa respective command/control station for each type of mission, i.e., astation for anti-submarine warfare, a station for littoral warfare, anda station for anti-mine warfare. The ship may also have a hull that,although not ideal for any particular type of mission, is at leastcompatible with all of the mission types for which the ship is designedfor.

One problem with such a multi-mission-type ship is that it is oftenlarger than it needs to be for a single type of mission. For example, ifa deck of the ship has a respective command/control station for eachtype of mission, then the deck, and most likely the ship, is bigger thanit would be if it included only a single station for a single type ofmission. Multi-mission ships are, therefore, high-value capital assets,are typically designed to carry a large crew to support the variousmissions, and are generally operated only in regions where high degreeof protection is supplied by other friendly ships.

Another problem is that such a multi-mission-type ship is typicallyinefficient. For example, if the ship is designed to perform three typesof mission and includes a respective command/control station for eachmission type, then two of the three stations are typically unused whenthe ship is on a mission.

Furthermore, as discussed above, the hull of such a multi-mission shipis typically not ideal for any of the mission types for which the shipis designed. That is, if the hull is ideal for one type of mission, itmay be incompatible with another type of mission. Therefore, whendesigning a hull that is compatible with multiple types of missions, adesigner must often design the hull as a compromise across all missions.

SUMMARY OF THE INVENTION

In one embodiment, a ship has a multi-mode hull where the draft,seakeeping, and payload-carrying capacity are varied to match therequirements of the required mission. A preferred embodiment of theinvention is directed to a ship having twin hulls with a first hullportion and a second hull portion with an interconnecting hullstructure, the ship also having a ballasting system within the twinhulls that is operable to adjust the draft of the ship in conjunctionwith the payload carried by the ship to perform the designated mission.The twin hulls are designed to have an adjustable hull depth accordingto the payload carried to perform the mission and augmented by theballasting system to optimize draft to meet mission requirements. As aresult, the ship operates in four distinct modes depicted graphically inFIGS. 5A through 5D as follows:

1) Very Shallow Draft (Also Referred to as “Logistics Mode”)

-   -   An additional displacement payload bay is affixed between the        hulls and accommodates heavy payloads. The added displacement of        the payload bay reduces the draft of the ship to enable the ship        to deliver the heavy payloads into very shallow water (i.e.        close to a beach). This mode is optimized for low speed        operations carrying heavy payloads in shallow water in calm to        moderate seas.        2) Shallow Draft Mode (Also Known as Catamaran Mode)    -   Payload (defined as the combination of, personnel, material and        fuel) carried by the ship is adjusted such that the draft of the        ship is shallow, similar to a catamaran. The reduced payload        (smallest payload of any of the four modes) enables the ship to        operate at its maximum speed. However, the limited fuel capacity        needed to achieve the light payload results in limited range for        this high-speed mode of operation. This mode is optimized for        high-speed operations carrying medium to light payloads in        shallow water or deep water in calm to moderate seas.        3) Moderate Draft Mode (Also Known as SWATH Mode)    -   As the payload in the ship increases beyond the light to        moderate payload of the Shallow Draft Mode (Catamaran mode), the        draft for the ship correspondingly increases since the        displacement of the ship must equal the total weight of the ship        plus the payload for the ship to remain afloat. The shape of the        ship's hulls enables the ship to operate as a        small-waterplane-area twin hull (SWATH), a hullform type well        known to provide excellent seakeeping in high seas. In this        Moderate Draft (SWATH) Mode, the ship is optimized to carry        moderate to heavy payloads for long distances at moderate speeds        in deep water in seas ranging from calm- to high-sea states.        4) Low Freeboard Mode (Also Known as Stealth Mode)    -   A Low Freeboard Mode is achieved by further increasing the        payload of the ship beyond the Moderate Draft Mode or by adding        ballast to the ship in the Moderate Draft Mode such that the        center portion of the ship between the two side hulls touches        the water. By eliminating the air gap between the water and the        underside of the center portion of the ship, the “shadow”        created by the air gap is eliminated and the ship has a reduced        radar and infrared signature and therefore has improved stealth        performance. This mode is optimized for low-speed operations in        areas of potentially high-threat detection activity with        moderate to heavy payloads.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings.

FIG. 1 is an isometric view of a multi-mission ship and an associatedmission module according to an embodiment of the invention.

FIG. 2 is a cutaway plan view of a multi-mission-type ship with amission module engaged according to an embodiment of the invention.

FIGS. 3A–3D illustrate a procedure for changing mission modules in theship of FIG. 1 according to an embodiment of the invention.

FIG. 4 illustrates an alternative procedure for changing mission modulesin the ship of FIG. 1 according to an embodiment of the invention.

FIGS. 5A–5D are end views of a ship having a multi-mode hull accordingto an embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 is an isometric view diagram of a multi-mission ship 100 and anassociated mission module 105 according to an embodiment of theinvention. The ship 100 includes a hull structure or frame 115 that isdesigned to accept one or more mission modules 105 (only one shown inFIG. 1). The frame 115 includes two lower hull portions 112 a and 112 b(called struts hereinafter) that extend down from a main body 113, (onestrut and lower hull 112 a extending down from the port side and onestrut and lower hull 112 b extending down from the starboard side) suchthat a receptacle or bay 110 is enclosed by the struts 112 a and 112 band the main body 113. The bay 110 creates a cavity such that water isfree to flow in and out of the bay area as the hull portions 112 a and112 b are only coupled to the main body 113 which stays above thesurface of the water because of the buoyancy of the struts 112 a and 112b. As such, a small watercraft or other floating objects may traverseinto the bay 110, below the main body 113, between the struts 112 a and112 b, and even out the back side of the ship 100 without evercontacting the any portion of the ship 100. Similarly, a mission module105 may also pass through the ship 100 in this manner, however, amission module 105 is typically engaged (by a lifting mechanismdescribed below) when it is directly under the ship 100. In analternative embodiment, the back side of the ship 100 is not open to thewater and objects may not pass completely through the cavity formed bythe bay 110.

Mission modules 105 are designed with different capabilities that, wheninterfaced with the ship 100, provide the ship 100 with mission-specificfunctionality for respective types of missions. That is, a missionmodule 105 is capable of carrying the equipment and supplies necessaryto conduct a specified mission. In this aspect, the ship 100 is somewhatanalogous to a personal computer that includes a mother board (analogousto the frame 115) designed to accept one or more plug in cards(analogous to the mission module 105) that give the computer a desiredfunctionality. Consequently, the ship 100 can be retrofitted for aparticular type of mission merely by swapping out one mission module 105for another. As discussed below, by designing a mission module 105 for aspecific mission, one can quickly retrofit the ship 100 while deployed(as opposed to being in a port) such that the ship's retrofit downtimeis reduced.

Generally, a mission module 105 comprises a watertight exterior and areinforced interior structure that includes associated propulsion andauxiliary systems such that the mission module is sufficiently seaworthy for short-distance transits from one ship or dock to the intendedhost frame.

More specifically, as discussed above, a mission module 105 typicallyincludes the equipment and other resources necessary to execute aparticular type of mission. For example, the module 105 may include,e.g., one or more mission-specific operator/control stations (notshown), a mission-specific computer system, quarters and supplies (notshown) for additional crew needed for the mission, hangers formission-specific equipment such as a helicopter or unmanned vehicle, anda tank for extra fuel.

The mission module 105 may also enhance the non-module, i.e., permanent,resources of the ship 100 for compatibility with the type of mission(s)that the module is designed for. For example, the ship 100 may include ageneral operator/control station (not shown), which the computer systemof the module 105 can configure for the corresponding type of missionvia an interface with the ship's computer system. Or, the module 105 maycarry extra fuel and supplies for a long-range mission.

Still referring to FIG. 1, although the module 105 is separable from theframe 115 of the ship 100, when installed in the bay 110, the moduleappears as an integral part of the ship according to an embodiment ofthe invention. For example, it is contemplated that in a module 105having operator/control stations and/or crew quarters, crew would enterand exit the module in the same manner that they would any other portionof the ship.

Mission-modules 105 are contemplated for a number of mission types,including, but not limited to, anti-mine warfare, anti-submarinewarfare, littoral operations, search and rescue, stealth delivery ofpersonnel or supplies, a logistics support system such as specialequipment transport or medical facilities, and/or a maritime interceptsystem. Alternatively, the module 105 may merely be used to provide theship 100 with additional fuel, supplies, or cargo space. Furthermore,although described as supporting a single type of mission, the missionmodule 105 may support multiple mission types. In addition, althoughshown as including a single bay 110, the frame 115 may include multiplebays 110 that can each receive a respective module 105.

FIG. 2 is a cutaway plan view of the multi-mission ship 100 with themission module 105 engaged within the bay 110 according to an embodimentof the invention.

The systems of the mission module 105 are connected to the respectivesystems of the ship 100 via ship-to-module interfaces as discussedbelow. Specifically, the ship-to-module interfaces include physicalconnections between the frame 115 and the mission module 105. Forexample, as shown in FIG. 2, cross-mounting structures 201 hold themission module 105 securely within the bay 110 while the mission moduleis engaged therein. A fuel interface 210 provides the capability totransfer fuel to and from the mission module 105. A water interface 211provides the capability to transfer fresh and/or waste water to and fromthe mission module 105. A computer and electrical interface 212 allowsthe transfer of electricity to and from the mission module 105, andallows the mission-module computer system to communicate with the frame115 computer system. Alternatively, if the mission module 105 includesno computer system, the interface 212 allows the frame 115 computer toconnect to and control the module. Other ship-to-module interfaces arecontemplated, but are not discussed for brevity.

After the mission module 105 enters the bay 110, crew members mate eachship-to-module interface on the mission module 105 with thecorresponding interface on the frame 115. Alternatively, the mating ofthe interfaces may be automated. In one implementation, the interfacesare universal for all ships 100 and mission modules 105 in a fleet sothat a crew can install virtually any mission module 105 in the bay 110of virtually any ship frame 115 using a common installation procedure.Likewise, a crew can remove virtually any mission module 105 from anybay 110 using a common removal procedure.

Alternate embodiments of the frame 115 and module 105 are contemplated.For example, although the bay 110 is described is being entirely below adeck (topside) of the ship 100, the frame 115 may have one or more deckopenings (not shown) that allow portions of the module 105 to be exposedfor use. For example, the module 105 may include a weapons turret (notshown) or an antenna array (not shown) that protrude through the deckopenings. Or, the module 105 may include an elevator that can carryplanes onto the ship deck via a deck opening.

FIGS. 3A–3D illustrate a procedure by which a crew replaces a firstmission module 105 a with a second mission module 105 b according to anembodiment of the invention. As discussed below, this procedure allows acrew to retrofit the ship 100 relatively quickly and while out at sea,and thus eliminates the need for the ship to return to port forretrofitting.

As shown in FIG. 3A, the ship 100 disengages the first mission module105 a. When disengaging the first mission module 105 a, crew members orother automatic means disconnect each ship-to-module interface (as shownin FIG. 2) between the frame 115 and the first mission module 105 a.Then, the crew adjusts the draft (i.e., the depth of the struts 112 aand 112 b in the water)) of the ship 100 to the proper level such thatthe first mission module 105 a is free to float out of the bay 110. Theship 100 may then begin moving away from the first mission module 105 ain the direction indicated by the arrow 351 to completely remove themodule 105 a from the bay 110. In an alternate implementation, the ship100 may include a crane or other lifting device (not shown) to removethe module 105 from the bay 110 and lower the module into the water. Forexample, the ship 100 may include straps (not shown) that engage thebottom of the module 105 a. The crew can, therefore, lower the module105 a into the water by loosening the straps.

Next, as illustrated in FIG. 3B, the ship 100 maneuvers away from thefirst mission module 105 a as indicated by the directional arrow 352.After moving far enough away from the first mission module 105 a, theship 100 then maneuvers into alignment with a second mission module 105b as indicated by directional arrow 353. Another ship (not shown)typically transports the second module 105 b to the ship 100 andrecovers the first module 105 a.

Next, as illustrated in FIG. 3C, the ship 100 traverses forward andtoward the second mission module 105 b as indicated by directional arrow354. The crew then aligns the bay 110 with the module 105 b, and sailtoward the mission module such that it enters the bay 110.

Finally, as illustrated in FIG. 3D, the ship 100 maneuvers into a finalalignment position such that the second mission module 105 b can besecured within the bay 110. Once the second mission module 105 b isfully within the bay 110, the crew (or automatic means) of the ship 100may then secure the second mission module within the bay. Next, eachship-to-module interface (FIG. 2) between the ship frame 115 and thesecond mission module 105 b is connected according to the requirementsof the functionality for which the second mission module is designed.Alternatively, where the draft of the ship 100 is such that the secondmission module 105 b cannot float into the bay 110, the crew may raisingthe second mission module out of the water and into the bay with a cranesystem or other similar lifting system (not shown). For example, themodule 105 b may be within or more loops formed by one or more straps(not shown) that hang down into the water (beneath the module 105 b)from the bay 110. Then, when the module 105 b is in the proper position,the crew can activate a winch or other device (not shown) to reel in thestraps, and thus pull the module 105 b up into the bay 110.

Once the second mission module 105 b is engaged within the bay 110, theship 100 is ready to begin its new mission. Still referring to FIGS.3A–3D, in another implementation, the module 105 can include a motor orother propelling device such that it can maneuver into the bay 110. Forexample, crew on board the module 105 can steer the module into the bay110, or crew on board the ship 100 can steer the module via remotecontrol.

FIG. 4 illustrates a procedure for removing and installing missionmodules according to another embodiment of the invention. For brevity,only the installation procedure is described here, it being understoodthat the removal procedure is merely the installation procedure inreverse.

Referring to FIG. 4, the frame 115 includes a ramp 150 that extends fromthe bay 110 via an opening at either the bow or stern of the ship 100.Using a winch assembly or other assembly (not shown), the crew pull themodule 105 up the ramp 150 and into the bay 110. The crew may increasethe draft of the ship, thus lowering the opening of the bay 110 towardthe water, to facilitate the installation of the module 105. After themodule 105 is fully within the bay 110, the crew retracts the ramp backinto the bay 110 (for example, beneath the installed module 105). Asdiscussed above, to remove the module 105, the crew extends the ramp 150and pushes the module out of the bay 110, down the ramp, and into thewater.

Once the mission module 105 is within the bay 110, the crew can securethe module within the bay 110 and can interface the various modulesystems to the frame 115 systems as discussed above in conjunction withFIGS. 1–3.

Referring to FIGS. 1–4, the modular design of the ship 100 provides manyadvantages in addition to those discussed above. For example, the module105 can be readied in port, and the crew can be trained in port, whilethe ship 100 is executing a mission with another module. Then, themodule 105 and crew can rendezvous with the ship 100, and the modulescan be swapped as described above so that that ship is ready for itsnext mission without coming into port.

And although the ship 100 is described as a water-going vessel, themodular concept is applicable to other vehicles. For example, anairplane may have a modular passenger cabin. Consequently, ground crewcan prepare the cabin and load the passengers while the plane is stillin the air or is being serviced. When the plane lands, the crew removesone passenger cabin from the plane, and installs another pre-boardedand/or and pre-prepared cabin into the plane. Therefore, the departingpassengers can effectively board the plane without having to wait forthe arriving passengers to disembark the plane or for the crew to cleanand restock the plane.

Still referring to FIGS. 1–4, although the modular design of the ship100 allows a crew to quickly and easily retrofit the ship for differenttypes of missions, the hull design of the ship may limit the types ofmissions that the ship can execute, or may limit the performance of theship when conducting mission.

FIGS. 5A–5D are end views of a ship 100 of FIG. 1 having a multi-modehull 510 that allows the ship 100 to execute a mission with a suitabletype of hull for that mission according to an embodiment of theinvention. The multi-mode hull 510 is a twin hull that combines aplurality of functions from several proven hull designs. The multi-modehull 510 allows the ship 100 to operate in at least the following fourmodes: a logistics mode (FIG. 5A), a catamaran mode (FIG. 5B), a SWATHmode (FIG. 5C), and a low freeboard mode (FIG. 5D). The crew can easilyswitch from one mode to another by merely adjusting the draft of theship 100 in conjunction with the payload (such as the module 500)carried by the ship to perform the required mission. The draft of theship 100 can be adjusted by adjusting the water carried in the ballasttanks (not shown) or through movable buoyant devices (also not shown)plus the payload carried by the ship to perform its mission.

Referring to FIG. 5A, in the logistics mode, the ship 100 rides higherin the water than it does in any other of the modes. A typical draft forthe hull 510 of a multi-mode hull ship 100 in the logistics mode is 9feet. Therefore, in the logistics mode, the ship 100 is better suited toshallow water tasks such as delivering a payload, such as module 500,close to shore. Examples of other such tasks include close shorelogistics support missions and ship to objective maneuvers (STOM). Ifadjusting the ballast of the ship 100 does not decrease the draftsufficiently to put the hull in the logistics mode, the crew can secureto the ship 100 a buoyant module 500 that provides additional buoyancysufficient to reduce the draft as needed.

Referring to FIG. 5B, in catamaran mode, the ship 100 rides relativelyhigh in the water such that the hull 510 acts as a catamaran hull. Atypical draft in catamaran mode is 12 feet. Therefore, in the catamaranmode, the hull 510 allows the ship 100 to travel at relatively highspeeds in a relatively energy efficient manner and in relatively shallowwater, and to undertake tasks that require these abilities. An exampleof such a task includes search and rescue and high-speed pursuit of anenemy craft.

Referring to FIG. 5C, in SWATH mode, the ship 100 rides lower in thewater than in the catamaran mode such that the hull 510 acts as a SWATHhull. In the SWATH mode, the ship 100 is slower and less energyefficient than in the catamaran mode, but it has better sea keeping andis better for transporting payloads or personnel long distances, andthus, is better for undertaking tasks that require these abilities. Atypical draft in SWATH mode is 20 feet.

Referring to FIG. 5D, in low freeboard mode, the ship 100 rides lower inthe water than in the SWATH mode such that the ship 100 has a lowprofile for stealth missions. That is, the portion of the ship 100 thatrides above the waterline in the low freeboard mode is minimized to makethe ship 100 less detectable than it is in the other three modes.Therefore, in the low freeboard mode, the ship 100 is suited forundertaking tasks that require secrecy or that otherwise require theship 100 to ride low in the water. Furthermore, any additional stealthfeatures, such as the shapes of the above water decks, need only beimplemented on the portion of the ship 100 that rides above thewaterline in the low freeboard mode, and not on the other largerportions of the ship 100 that ride above the waterline in the othermodes. A typical draft in the low freeboard mode is 32 feet.

Other embodiments of the multi-mode hull 510 are contemplated. Forexample, the hull 510 may allow the ship 100 to operate in one or moremodes that are intermediate to the four modes described above.Furthermore, one may design a multi-mode hull that has more or fewerthan four modes, where some or all of these modes are different than thefour modes described above.

Still referring to FIGS. 5A–5D, the ship 100 may operate in one or moreof the above-described hull modes when performing a single mission. Forexample, suppose the ship is to perform an anti-submarine-warfaremission at a location that is remote from the location where the crewloads the anti-submarine mission module 105 into the bay 110. At first,because the ship 100 (the frame 115, the module 105, or both) is loadedwith fuel and supplies for the mission, the draft of the ship may besuch that the ship operates in the SWATH mode (FIG. 5C). If the missionis secret, then the crew may add additional ballast (typically water) tocause the ship 100 to operate in the low-freeboard (stealth) mode (FIG.5D). When the ship 100 reaches the mission location, then the fuel andsupplies may be depleted sufficiently such that with the removal of aproper amount of ballast, the ship can operate in the catamaran mode(FIG. 5B) to, e.g., chase a submarine. [49] The preceding discussion ispresented to enable a person skilled in the art to make and use theinvention. The general principles described herein may be applied toembodiments and applications other than those detailed above withoutdeparting from the spirit and scope of the present invention. Forexample, although a twin-hull ship is discussed above, ships havingother types of multi-mode hulls such as dynamic-lift hullforms arecontemplated. Therefore, the present invention is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed or suggestedherein.

1. A vessel, comprising: a propulsion device; a hull carrying the propulsion device and having at least three operating modes in which the hull is operable to be moved by the propulsion device from a first geographic location to a second geographic location, wherein the at least three operating modes includes a SWATH mode; and a system operable to select one of the operating modes.
 2. The vessel of claim 1 wherein the system comprises a ballast system that is operable to select one of the operating modes by adjusting the draft of the vessel to a level that corresponds to the selected operating mode.
 3. The vessel of claim 1 wherein the system comprises a ballast system that is operable to select one of the operating modes by adjusting a level of ballast within the vessel.
 4. The vessel of claim 1, further comprising: a payload; and wherein the system comprises a ballast system that is operable to select one of the operating modes by adjusting the draft of the vessel using the payload.
 5. A water vessel, comprising: a hull having a first hull portion and a second hull portion and having at least three operating modes in which the hull is operable to travel from a first geographic location to a second geographic location, wherein the at least three operating modes includes a SWATH mode; and a ballast system disposed within the hull and operable to select one of the operating modes corresponding to a predetermined mission by adjusting, during traveling from the first geographic location to the second geographic location, the draft of the vessel.
 6. The vessel of claim 5 wherein the ballast system is operable to select a catamaran mode of operation by adjusting the draft of the vessel such that the hull is in a catamaran position with respect to the surface of the water.
 7. The vessel of claim 5 wherein the ballast system is operable to select the SWATH mode of operation by adjusting the draft of the vessel such that the hull is in a SWATH position with respect to the surface of the water.
 8. The vessel of claim 5 wherein the ballast system is operable to select a low freeboard mode of operation by adjusting the draft of the vessel such that the hull is in a low freeboard position with respect to the surface of the water.
 9. The vessel of claim 5 wherein the ballast system is operable to select a shallow water mode of operation by adjusting the draft of the vessel such that the hull is in a shallow water position with respect to the surface of the water.
 10. The water vessel of claim 5, comprising: a payload; and wherein the ballast system is operable to adjust the draft of the vessel using the payload.
 11. The water vessel of claim 5 wherein the first hull portion is parallel or approximately parallel to the second hull portion.
 12. A method, comprising: selecting one of at least three hull operating modes for a water vessel carrying a propulsion device, the vessel operable to be moved by the propulsion device in each of the hull operating modes from a first geographic location to a second geographic location, wherein the at least three hull operating modes includes a SWATH mode; and operating the vessel in the selected hull mode.
 13. The method of claim 12 wherein selecting the hull operating mode comprises setting a draft of the water vessel to a level that corresponds to the hull operating mode.
 14. The method of claim 12 wherein the hull of the vessel, in the selected hull operating mode, has a corresponding hydrodynamic property that is related to a submerged portion of the hull.
 15. The method of claim 12 wherein selecting the hull operating mode comprises adjusting the draft of the water vessel to a corresponding level.
 16. The method of claim 12 wherein selecting the hull operating mode comprises adjusting the amount of ballast on the water vessel.
 17. The method of claim 12 wherein selecting the hull operating mode comprises adjusting the amount of payload on the vessel.
 18. The method of claim 12 wherein selecting the hull operating mode comprises adjusting the amount of payload and ballast on the water vessel.
 19. The method of claim 12 wherein selecting the hull operating mode comprises adjusting a position of a payload relative to the water line.
 20. The method of claim 12 wherein selecting one of multiple hull operating modes includes selecting a very shallow draft mode.
 21. The method of claim 12 wherein selecting one of multiple hull operating modes includes selecting a shallow draft mode.
 22. A vessel, comprising: a propulsion device; a hull carrying the propulsion device and having multiple operating modes in which the hull is operable to be moved by the propulsion device from a first geographic location to a second geographic location, wherein the multiple operating modes includes a very-shallow-draft mode; a payload; and a system operable to select one of the operating modes, wherein the system comprises a ballast system that is operable to select one of the operating modes by adjusting the draft of the vessel using the payload.
 23. A water vessel, comprising: a hull having a first hull portion and a second hull portion and having multiple operating modes in which the hull is operable to travel from a first geographic location to a second geographic location, wherein the multiple operating modes includes a logistics mode; and a ballast system disposed within the hull and operable to select one of the operating modes corresponding to a predetermined mission by adjusting, during traveling from the first geographic location to the second geographic location, the draft of the vessel, wherein the ballast system is operable to select a SWATH mode of operation by adjusting the draft of the vessel such that the hull is in a SWATH position with respect to the surface of the water.
 24. A water vessel, comprising: a hull having a first hull portion and a second hull portion and having multiple operating modes in which the hull is operable to travel from a first geographic location to a second geographic location, wherein the multiple operating modes includes a logistics mode; a payload; and a ballast system disposed within the hull and operable to select one of the operating modes corresponding to a predetermined mission by adjusting, during traveling from the first geographic location to the second geographic location, the draft of the vessel using the payload.
 25. A method, comprising: selecting one of multiple hull operating modes for a water vessel carrying a propulsion device, the vessel operable to be moved by the propulsion device in each of the hull operating modes from a first geographic location to a second geographic location, wherein the multiple hull operating modes includes a very-shallow-draft mode, and wherein selecting the hull operating mode comprises adjusting the amount of payload on the vessel; and operating the vessel in the selected hull mode.
 26. A method, comprising: selecting one of multiple hull operating modes for a water vessel carrying a propulsion device, the vessel operable to be moved by the propulsion device in each of the hull operating modes from a first geographic location to a second geographic location, wherein the multiple hull operating modes includes a very-shallow-draft mode, and wherein selecting the hull operating mode comprises adjusting the amount of payload and ballast on the water vessel; and operating the vessel in the selected hull mode.
 27. A method, comprising: selecting one of multiple hull operating modes for a water vessel carrying a propulsion device, the vessel operable to be moved by the propulsion device in each of the hull operating modes from a first geographic location to a second geographic location, wherein the multiple hull operating modes includes a very-shallow-draft mode, and wherein selecting the hull operating mode comprises adjusting a position of a payload relative to the water line; and operating the vessel in the selected hull mode. 